Host condition factor and Gastrointestinal
protozoa and helminth parasites in Synodontis clarias, Synodontis
filamentosus and Chrysichthys
nigrodigitatus in Lekki lagoon, Lagos,
Nigeria were investigated from September, 2014 to February, 2015. Eighty specimens each of both  Synodontis clarias and Chrysichthys nigrodigitatus and fifty 
of  Synodontis  filamentosus   were examinedfrom  Lekki lagoon 
and dissected for parasitological investigation
The. Condition factors of all individual fishes were determined. Median
condition (K < 1.41 and K > 1.41) for Synodontis clarias, (K <
2.14 and K > 2.14) for Synodontis filamentosus and (K < 1.49 and K
> 1.49) for Chrysichthys nigrodigitatus were used in grouping the individuals. Heterogeneous infection of intestinal protozoa
in C. nigrodigitatus were greater among the low condition individuals; 0.18 compared to high condition individuals with 0.10. This also aplies to S.
clarias, low condition individuals; 0.28, while high condition individuals
had infection rate of 0.13. S. filamentosus showed a different trend,
the rate of infection were greater among the high condition individuals; 0.15,
compared to low condition of 0.10. The rate of infection of parasitic helminths
in C. nigrodigitatus, S. clarias and S. filamentosus were
higher among low condition individuals compared to high condition individuals.
High condition individuals of the fish species harbor more parasites than low
condition individuals. Infected individuals of low condition factor (K <
1.49) of C. nigrodigitatus had a greater histopathological alteration index (HAI,
12.0) compared to the high condition individuals (HAI, 6.0). These individuals
had from mild to severe ulceration of the mucosa and congestion of the blood
vessels. In infected individuals of low condition factor (K < 1.41), (K <
2.14) of S. clarias and S . filamentosus,
there were mucosal edema and haemorrhage in their intestinal walls. They also
had greater histopathological alteration index (HAI, 24.0), (HAI, 18.0)
compared to the high condition individuals (HAI, 10.0) and (HAI, 4.0)
respectively.  These low
condition infected individuals in the population are multi-stressed and have
showed significant pathological responses in their tissues.